A nonaqueous electrolyte battery in which charge and discharge are performed by migration of lithium ions between a negative electrode and a positive electrode is actively researched as a high energy-density battery.
In addition to the use as a power supply for small electronic devices, the nonaqueous electrolyte battery is expected to be used as a medium to large power supply such as in-vehicle use or stationary use. For such a medium to large-scale use, the nonaqueous electrolyte battery is required to exhibit a life performance and a high-level safety. Further, the nonaqueous electrolyte battery is desired to exhibit high input-and-output performances.
A known example of a nonaqueous electrolyte battery exhibit a life performance and a high-level safety includes a nonaqueous electrolyte battery in which a spinel-type lithium titanate is used for a negative electrode. However, since the Li-insertion-and-extraction potential of the spinel-type lithium titanate is high (1.55 V (vs. Li/Li+)), a nonaqueous electrolyte battery in which the spinel lithium titanate is used for the negative electrode has a low battery voltage. Further, the spinel-type lithium titanate exhibits a flat charge-discharge curve in the lithium insertion-and-extraction potential range and shows a very small change in potential accompanying a change in state-of-charge.